Improved Boundary Element Methods for Predicting Sectional Hydrodynamic Coefficients for Strip Theory Ship Motion Programs.
Abstract
This technical memorandum presents two improved boundary element methods for predicting hydrodynamic coefficients of two dimensional sections. The first method is a source distribution method, while the second is a direct method for determining velocity potential. A major objective of these improved methods is to eliminate errors due to irregular frequencies, which currently exist in the close-fit method used by the strip theory program SHIPMO. Both new methods successfully eliminate problems caused by horizontal and vertical line segments with the close-fit method. To eliminate irregular frequencies of surface-piercing sections, the source distribution method employs additional sources on a deck lid at the waterline. The introduction of a deck lid eliminates some irregular frequencies but introduces new irregular frequencies. Alternatively, a modified direct method effectively eliminates all irregular frequencies. Future strip theory implementations should incorporate this modified direct method. This technical memorandum also reviews low and high frequency limits of hydrodynamic coefficients.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 1996
- Accession Number
- ADA307891
Entities
People
- Kevin A. Mctaggart
Organizations
- Defence Research and Development Canada